Organic light emitting display device

ABSTRACT

An organic light emitting display device includes: a substrate; a display unit on the substrate; and an encapsulation layer on the display unit, the encapsulation layer including a plurality of inorganic layers and a plurality of organic layers, the plurality of inorganic layers and the plurality of organic layers being alternately located, and the plurality of organic layers being at a region where the plurality of inorganic layers is located. The plurality of inorganic layers covers the display unit and is sequentially on the substrate, and areas of each of the inorganic layers are increased moving in a direction away from the display unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean PatentApplication No. 10-2012-0131458, filed on Nov. 20, 2012, with the KoreanIntellectual Property Office, the present invention of which isincorporated herein in its entirety by reference.

TECHNICAL FIELD

Embodiments of the present invention relate to an organic light emittingdisplay device, and more particularly, to an organic light emittingdisplay device that reduces (or prevents) penetration of moisture intoends of inorganic layers and a lifting phenomenon between inorganiclayers, by increasing areas of a plurality of inorganic layers includedin a thin film encapsulation layer in sequence.

BACKGROUND

An organic light emitting display device is a self-emission displaydevice which has an organic light emitting diode that emits light todisplay an image. Since an organic light emitting display devicegenerally does not require a separate light source unlike a liquidcrystal display, it is possible to relatively reduce a thickness andweight thereof. In addition, an organic light emitting display devicemay exhibit characteristics such as low power consumption, highluminance, and a rapid response speed.

In an organic light emitting display device, a display unit maydeteriorate due to penetration of oxygen or moisture. Accordingly, inorder to reduce (or prevent) oxygen or moisture from penetrating fromthe outside, an encapsulation structure for sealing and protecting thedisplay unit may be used.

For example, an encapsulation structure including a thin filmencapsulation structure which covers the display unit by a multilayer,in which organic layers and inorganic layers are alternately laminated,has been adopted. That is, the display unit is sealed by alternatelylaminating the organic layers and the inorganic layers on the displayunit of the substrate. Here, the organic layers may function to giveflexibility to a flat panel display, and the inorganic layers mayfunction to reduce (or prevent) penetration of oxygen or moisture.

SUMMARY

Aspects of embodiments of the present invention provide an organic lightemitting display device for improving an encapsulation structure to moreefficiently protect an organic light emitting diode unit. For example,some embodiments of the present invention provide an organic lightemitting display device for reducing (or preventing) a liftingphenomenon of edges of inorganic layers and more efficiently blockingmoisture and oxygen from penetrating.

An exemplary embodiment of the present invention provides an organiclight emitting display device, including: a substrate; a display unit onthe substrate; and an encapsulation layer on the display unit, theencapsulation layer including a plurality of inorganic layers and aplurality of organic layers, the plurality of inorganic layers and theplurality of organic layers being alternately located, and the pluralityof organic layers being at a region where the plurality of inorganiclayers is located. The plurality of inorganic layers covers the displayunit and is sequentially on the substrate, and areas of each of theinorganic layers are increased moving in a direction away from thedisplay unit.

An outermost layer of the encapsulation layer may be formed by acorresponding one of the inorganic layers.

An edge of the encapsulation layer may include the plurality ofinorganic layers sequentially on the substrate, and in the plurality ofinorganic layers, an upper inorganic layer may cover an end of a lowerinorganic layer.

In the plurality of organic layers, areas of each of the organic layersmay be increased moving in the direction away from the display unit.

The organic light emitting display device may further include anencapsulation protecting layer covering the encapsulation layer.

The encapsulation protecting layer may be an organic layer.

The display unit may include a first electrode on the substrate; anemission layer on the first electrode; and a second electrode on theemission layer.

At least one of a hole injection layer or a hole transfer layer may bebetween the first electrode and the emission layer.

At least one of an electron transport layer or an electron injectionlayer may be between the emission layer and the second electrode.

A capping layer may be between the display unit and the encapsulationlayer.

The capping layer may include a transparent material having ultravioletlight absorbing capacity.

A thickness of each inorganic layer of the plurality of inorganic layersmay be in a range of about 10 nm to about 50 nm.

A thickness of each organic layer of the plurality of organic layers maybe in a range of about 10 nm to about 50 nm.

Another exemplary embodiment of the present invention provides amanufacturing method of an organic light emitting display device, themethod including: forming a display unit on a substrate; and forming anencapsulation layer on the display unit, the forming of theencapsulation layer including: forming a first inorganic layer on thedisplay unit; and laminating organic layers and inorganic layers on thefirst inorganic layer in sequence, the organic layers being in a regionwhere the inorganic layers are disposed. An upper inorganic layercompletely covers a lower inorganic layer and the organic layers.

The organic layers and the inorganic layers may be laminated many times.

The number of times of laminating the organic layers and the inorganiclayers may be 2 to 30 times.

An outermost layer of the encapsulation layer may be formed by acorresponding one of the inorganic layers.

The upper inorganic layer may cover an end of the lower inorganic layer.

The manufacturing method of the organic light emitting display devicemay further include forming an encapsulation protecting layer coveringthe encapsulation layer, after the laminating the organic layers and theinorganic layers.

The forming the display unit may include forming a first electrode onthe substrate; forming an emission layer on the first electrode; andforming a second electrode on the emission layer.

The manufacturing method of the organic light emitting display devicemay further include forming a capping layer on the display unit, afterthe forming the display unit.

A thickness of each of the inorganic layers may be in a range of about10 nm to 50 nm.

A thickness of each of the organic layers may be in a range of about 10nm to 50 nm.

In the organic light emitting display device according to an exemplaryembodiment of the present invention, it is possible to reduce (orprevent) a lifting phenomenon between inorganic layers which are incontact with each other and reduce (or block) penetration of oxygen ormoisture into edges of the inorganic layers.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view schematically illustrating an organiclight emitting display device according to an exemplary embodiment ofthe present invention.

FIG. 2 is a cross-sectional view enlarging an encapsulation layer in theorganic light emitting display device of FIG. 1.

FIG. 3 is a diagram illustrating the organic light emitting displaydevice illustrated in FIG. 1 in more detail.

FIG. 4 is a cross-sectional view illustrating an organic light emittingdisplay device according to another exemplary embodiment of the presentinvention.

FIGS. 5A to 5C are diagrams schematically illustrating a manufacturingprocess of an organic light emitting display device according to anexemplary embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present invention will bedescribed in more detail with reference to the accompanying drawings.However, the scope of the present invention is not limited to thefollowing examples and drawings. Exemplary embodiments to be describedbelow and illustrated in the drawings may include various equivalencesand modifications.

The terminology used in this specification is used in order to expressexemplary embodiments of the present invention and may depend on theintention of users or operators or the custom in the art to which thepresent invention belongs. Accordingly, the terminology should be viewedin the context of the details described throughout this specification.

For reference, respective components and shapes thereof may beschematically drawn or exaggeratedly drawn in the accompanying drawingsfor ease of understanding. Like reference numerals designate likeelements throughout the drawings.

Further, it will be understood that when a layer or an element isdescribed as being “on” another layer or element, it may be directlydisposed on another layer or element, or an intervening layer or elementmay also be present.

FIG. 1 is a cross-sectional view schematically illustrating an organiclight emitting display device according to an exemplary embodiment ofthe present invention. Referring to FIG. 1, the organic light emittingdisplay device according to an exemplary embodiment of the presentinvention includes a substrate 100, a display unit 200 formed on thesubstrate 100, and an encapsulation layer 300 formed on the display unit200.

The substrate 100 may be made of various materials such as a glasssubstrate, a quartz substrate, and a transparent resin substrate, andmay be formed by using a flexible material. The transparent resinsubstrate which may be used as the substrate 100 may contain a polyimideresin, an acrylic resin, a polyacrylate resin, a polycarbonate resin, apolyether resin, a polyethylene terephthalate resin, a sulfonic acidresin, and the like.

In the case where the organic light emitting diode display is a rearemission type and an image is displayed toward the substrate 100 side,the substrate 100 may be made of a light transmitting material, but inthe case of a front emission type where an image is displayed toward theencapsulation layer 300 side, the substrate 100 may not necessarily bemade of a light transmitting material.

The display unit 200 is an element including an emission layer 230. Adetailed configuration according to an embodiment will be describedbelow.

In one embodiment, the encapsulation layer 300 has a structure in whichorganic layers 320 and inorganic layers 310 are alternately laminated.In order to reduce (or prevent) oxygen or moisture from penetrating fromthe outside, the organic layers 320 may be positioned at the inner sideof the encapsulation layer 300, adjacent to the display unit, and theinorganic layers 310 may be positioned toward the outer side ofencapsulation layer, away from the display unit.

The inorganic layers 310 may be laminated to have substantially the samesize, and in this case, a space may be formed between ends of twoinorganic layers 310 which are in contact with each other at edges ofthe inorganic layers 310, and as a result, a lifting phenomenon betweenthe inorganic layers 310 occurs, and oxygen or moisture may penetratebetween the ends of the inorganic layers 310.

FIG. 2 is a cross-sectional view enlarging an encapsulation layer in theorganic light emitting display device of FIG. 1.

Referring to FIG. 2, the encapsulation layer 300 may include a pluralityof inorganic layers 310 and a plurality of organic layers 320. Theplurality of inorganic layers 310 and the plurality of organic layers320 may be alternately laminated.

The outermost layer of the encapsulation layer 300 is constituted by theinorganic layer 310.

In FIG. 2, the plurality of inorganic layers 310 includes a firstinorganic layer 311, a second inorganic layer 312, and a third inorganiclayer 313. However, embodiments of the present invention are not limitedthereto, and the inorganic layers 310 may be formed with four or morelayers.

In FIG. 2, the plurality of organic layers 320 includes a first organiclayer 321 and a second organic layer 322. However, embodiments of thepresent invention are not limited thereto, and the organic layers 320may be formed with three or more layers.

The plurality of organic layers 320 may be formed in a region where theplurality of inorganic layers 310 is disposed.

For example, the first organic layer 321 may be formed in a region wherethe first inorganic layer 311 and the second inorganic layer 312 aredisposed, and the second organic layer 322 may be formed in a regionwhere the second inorganic layer 312 and the third inorganic layer 313are disposed. That is, the organic layers 320 may be completely coveredby the inorganic layers 310 formed on the organic layers 320.

For example, the first organic layer 321 may be formed on the firstinorganic layer 311 and formed in the region of the first inorganiclayer 311. The second inorganic layer 312 may be formed on the firstorganic layer 321, and the second inorganic layer 312 may completelycover the first organic layer 321 up to the first inorganic layer 311.The second organic layer 322 and the third inorganic layer 313 may becontinuously formed by the method.

The plurality of inorganic layers 310 may cover the display unit 200 andmay be laminated on the substrate 100 in sequence, and areas thereof maybe increased moving in a direction away from the display unit 200.

For example, an area of the first inorganic layer 311 may be smallerthan an area of the second inorganic layer 312, and an area of thesecond inorganic layer 312 may be smaller than an area of the thirdinorganic layer 313. An area of the plurality of inorganic layers 310may be formed to cover all of the laminated inorganic layers 310 andorganic layers 320 (e.g., the lower laminated inorganic layers 310 andorganic layers 320).

According to an embodiment, since the areas of the plurality of organiclayers 320 are smaller than the areas of the plurality of inorganiclayers 310, the edge of the encapsulation layer 300 may have a structurein which the plurality of inorganic layers 310 is sequentially laminatedon the substrate 100. That is, the plurality of inorganic layers 310 mayhave a structure in which the upper inorganic layer covers the end ofthe lower inorganic layer. The upper inorganic layer may mean that theinorganic layer is relatively far away from the substrate 100 in avertical direction of the substrate 100, and the lower inorganic layermay mean that the inorganic layer is relatively close to the substrate100 in the vertical direction of the substrate 100.

Accordingly, since the upper inorganic layer covers up to the lowerinorganic layer, the organic light emitting display device according toan exemplary embodiment of the present invention may suppress thelifting phenomenon between the adjacent layers at the edge of theencapsulation layer 300 and may reduce (or block) penetration of oxygenor moisture.

Meanwhile, the areas of the plurality of organic layers 320 may beincreased moving in a direction away from the display unit 200. Sincethe areas of the plurality of inorganic layers 310 are increased movingin a direction away from the display unit 200, the areas of theplurality of organic layers 320 included in the region where theplurality of inorganic layers 310 is disposed are increased inproportion to the degree that the areas of the plurality of inorganiclayers 310 are increased.

Thin film materials which may be used as the inorganic layers 310 andthe organic layers 320, and a laminating method of the inorganic layers310 and the organic layers 320, are without specific limitation and maybe any material or method known in the art.

For example, the thin film material which is used as the inorganiclayers 310 may contain at least one selected from a group constituted bysilicon nitride, aluminum nitride, zirconium nitride, titanium nitride,hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, andtitanium oxide.

The thin film material which is used as the organic layers 320 maycontain at least one selected from a group constituted by epoxy,acrylate, urethane acrylate, polyurea, polyacrylate, PTCDA, BPDA, andPMDA.

However, any inorganic thin film materials or organic thin filmmaterials which are known in the art may be used as the materials of theinorganic layers 310 or the organic layers 320 of the present invention.

The inorganic layers 310 and the organic layers 320 may be formed byusing a spin coating process, a printing process, a sputtering process,a chemical vapor deposition (CVD) process, an atomic layer deposition(ALD) process, a plasma enhanced chemical vapor deposition (PECVD)process, a high density plasma-chemical vapor deposition (HDP-CVD)process, a vacuum deposition process, and the like according to amaterial for forming the encapsulation layer 300.

A thickness of each inorganic layer 310 configuring the plurality ofinorganic layers 310 may be in the range of 10 nm to 50 nm.

When the thickness of each inorganic layer 310 is less than 10 nm, thepenetration of moisture and oxygen may not be sufficiently blocked, andwhen the thickness of each inorganic layer 310 is more than 50 nm, thethickness of the organic light emitting display device may be increasedand thus the organic light emitting display device may be an obstacle tothinness.

Meanwhile, as the inorganic layers 310 become thicker, the stress of theinorganic layers may be increased and thus the lifting phenomenon of theinorganic layers 310 may occur.

A thickness of each organic layer 320 configuring the plurality oforganic layers 320 may be in the range of 10 nm to 50 nm. When thethickness of each organic layer 320 is less than 10 nm, it may bedifficult to ensure flexibility of the organic light emitting displaydevice, and when the thickness of each organic layer 320 is more than 50nm, there may be a problem in that the thickness of the organic lightemitting display device is increased. However, the numerical ranges ofthe inorganic layers 310 and the organic layers 320 may be changedaccording to a use and a function of a thin film encapsulation layer.

FIG. 3 is a diagram illustrating the organic light emitting displaydevice illustrated in FIG. 1 in more detail.

Referring to FIG. 3, the display unit 200 may include a first electrode210 formed on the substrate 100, a pixel defining layer (PDL) 220 formedbetween the first electrodes 210, an emission layer 230 formed on thefirst electrode 210, and a second electrode 240 formed on the emissionlayer 230.

In the case where an organic light emitting display device is a frontemission type, the first electrode 210 may contain at least one of gold(Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr),molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd),titanium (Ti), and a compound thereof. In addition, the second electrode240 may contain at least one of indium tin oxide (ITO) and indium zincoxide (IZO), which are transparent conductive oxides.

In the case where the organic light emitting display device is a rearemission type, the first electrode 210 may contain at least one ofindium tin oxide (ITO) and indium zinc oxide (IZO), which aretransparent conductive oxides having a high work function. In addition,the second electrode 240 may be made of metal having a low workfunction, that is, alkali metals such as lithium (Li) and cesium (Cs),alkaline earth metals such as magnesium (Mg), calcium (Ca) and strontium(Sr), and a compound thereof.

The first electrode 210 and the second electrode 240 may contain anymaterials which are known in the art.

The pixel defining layer 220 may be made of a material having aninsulation property to partition the first electrodes 210 into pixelunits. For example, the pixel defining layer 220 may be disposed at anedge of the first electrode 210 to partition the first electrodes intopixel unit and define pixel areas. The pixel defining layer 220 maycover the edge of the first electrode 210.

The emission layer 230 may include a red emission layer, a greenemission layer, and a blue emission layer.

A hole injection layer (HIL) 250 and a hole transfer layer (HTL) 260 maybe included between the first electrode 210 and the emission layer 230,and an electron transport layer (ETL) 270 and an electron injectionlayer (EIL) 280 may be included between the emission layer 230 and thesecond electrode 240.

A capping layer 400 may be disposed between the display unit 200 and theencapsulation layer 300, and the capping layer 400 may be made of atransparent material having ultraviolet light absorbing capacity.

FIG. 4 is a cross-sectional view illustrating an organic light emittingdisplay device according to another exemplary embodiment of the presentinvention. Referring to FIG. 4, the organic light emitting displaydevice according to another exemplary embodiment of the presentinvention may further include an encapsulation protecting layer 500covering the encapsulation layer 300.

The encapsulation protecting layer 500 may seal the edge of theencapsulation layer 300 once more. Accordingly, the encapsulationprotecting layer 500 may reduce (or prevent) the lifting phenomenonbetween the inorganic layers 310, increase an effect of reducing (orblocking) the penetration of oxygen or moisture, and better protect theorganic light emitting display device from mechanical and physicaldamages applied from the outside.

The encapsulation protecting layer 500 may be made of an organicmaterial, and the organic material may be the same as the material ofthe plurality of organic layers 320.

A thickness of the encapsulation protecting layer 500 may beapproximately 1 to 20 μm. When the thickness of the encapsulationprotecting layer 500 is less than 1 μm, the organic light emittingdisplay device may be damaged due to external factors, and when thethickness of the encapsulation protecting layer 500 is more than 20 μm,there may be a problem in that the thickness of the organic lightemitting display device is increased.

FIGS. 5A to 5C are diagrams schematically illustrating a manufacturingprocess of the organic light emitting display device according to anexemplary embodiment of the present invention.

In step (a), the first inorganic layer 311 is formed on the substrate100 having the display unit 200 (see FIG. 5A). In step (b), theencapsulation layer 300 is formed on the display unit 200.

Step (b) includes step (c) and step (d) (see FIG. 5B).

In step (c), the first inorganic layer 311 covers the entire displayunit 200 and a part of the substrate 100.

After step (c), in step (d), the first organic layer 321 is formed onthe first inorganic layer 311, and the second inorganic layer 312 coversthe first organic layer 321 and the first inorganic layer 311 (see FIG.5B).

After step (d), laminating the inorganic layers 310 and the organiclayers 320 in sequence may be repeated one or more times.

For example, after forming the second inorganic layer 312, the secondorganic layer 322 is formed on the second inorganic layer 312, and thethird inorganic layer 313 covers the second inorganic layer 312 and thesecond organic layer 322 (see FIG. 5C). That is, in each step of formingthe plurality of inorganic layers 310, the areas of the plurality ofinorganic layers 310 may be largely formed to cover up to the ends ofthe already formed inorganic layers 310. The laminating of the pluralityof organic layers 320 and the plurality of inorganic layers 310 insequence may be performed 2 to 30 times.

From the foregoing, it will be appreciated that various embodiments ofthe present invention have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present invention.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims and their equivalents.

What is claimed is:
 1. An organic light emitting display device,comprising: a substrate; a display unit on the substrate; and anencapsulation layer on the display unit, wherein the encapsulation layercomprises a plurality of inorganic layers and a plurality of organiclayers, the plurality of inorganic layers and the plurality of organiclayers being alternately located, and the plurality of organic layersbeing at a region where the plurality of inorganic layers is located,wherein the plurality of inorganic layers covers the display unit and issequentially on the substrate, and areas of each of the inorganic layersare increased in a direction away from the display unit, and wherein anedge of the encapsulation layer comprises the plurality of inorganiclayers sequentially on the substrate, and in the plurality of inorganiclayers, an upper inorganic layer covers an end of a lower inorganiclayer.
 2. The organic light emitting display device of claim 1, whereinan outermost layer of the encapsulation layer is formed by acorresponding one of the inorganic layers.
 3. The organic light emittingdisplay device of claim 1, wherein the upper inorganic layer contactsthe end of the lower inorganic layer.
 4. The organic light emittingdisplay device of claim 1, wherein in the plurality of organic layers,areas of each of the organic layers are increased moving in thedirection away from the display unit.
 5. The organic light emittingdisplay device of claim 1, further comprising: an encapsulationprotecting layer covering the encapsulation layer.
 6. The organic lightemitting display device of claim 5, wherein the encapsulation protectinglayer is an organic layer.
 7. The organic light emitting display deviceof claim 1, wherein the display unit comprises a first electrode on thesubstrate; an emission layer on the first electrode; and a secondelectrode on the emission layer.
 8. The organic light emitting displaydevice of claim 7, wherein at least one of a hole injection layer or ahole transfer layer is between the first electrode and the emissionlayer.
 9. The organic light emitting display device of claim 7, whereinat least one of an electron transport layer or an electron injectionlayer is between the emission layer and the second electrode.
 10. Theorganic light emitting display device of claim 1, wherein a cappinglayer is between the display unit and the encapsulation layer.
 11. Theorganic light emitting display device of claim 10, wherein the cappinglayer comprises a transparent material having ultraviolet lightabsorbing capacity.
 12. The organic light emitting display device ofclaim 1, wherein a thickness of each inorganic layer of the plurality ofinorganic layers is in a range of about 10 nm to about 50 nm.
 13. Theorganic light emitting display device of claim 1, wherein a thickness ofeach organic layer of the plurality of organic layers is in a range ofabout 10 nm to about 50 nm.
 14. A manufacturing method of an organiclight emitting display device, the method comprising: forming a displayunit on a substrate; and forming an encapsulation layer on the displayunit, wherein the forming of the encapsulation layer comprises: forminga first inorganic layer on the display unit; and laminating organiclayers and inorganic layers on the first inorganic layer in sequence,the organic layers being in a region where the inorganic layers aredisposed, wherein areas of each of the inorganic layers are increased ina direction away from the display unit, and wherein an edge of theencapsulation layer comprises the inorganic layers sequentially on thesubstrate, and in the inorganic layers, an upper inorganic layercompletely covers a lower inorganic layer.
 15. The manufacturing methodof claim 14, wherein the organic layers and the inorganic layers arelaminated many times.
 16. The manufacturing method of claim 15, whereinthe number of times of laminating the organic layers and the inorganiclayers is 2 to 30 times.
 17. The manufacturing method of claim 14,wherein an outermost layer of the encapsulation layer is formed by acorresponding one of the inorganic layers.
 18. The manufacturing methodof claim 14, wherein the upper inorganic layer covers an end of thelower inorganic layer.
 19. The manufacturing method of claim 14, furthercomprising: forming an encapsulation protecting layer covering theencapsulation layer, after the laminating the organic layers and theinorganic layers.
 20. The manufacturing method of claim 14, wherein theforming the display unit comprises forming a first electrode on thesubstrate; forming an emission layer on the first electrode; and forminga second electrode on the emission layer.
 21. The manufacturing methodof claim 14, further comprising: forming a capping layer on the displayunit, after the forming the display unit.
 22. The manufacturing methodof claim 14, wherein a thickness of each of the inorganic layers is in arange of about 10 nm to 50 nm.
 23. The manufacturing method of claim 14,wherein a thickness of each of the organic layers is in a range of about10 nm to 50 nm.